Examples.
DATA FOR COTTON ROPES, WHEN V = 4700 FT. PER M.
(Messrs. MUSGRAVE.)
537
Dia. of rope.
Area of circle.
Weight per foot.
3*1 t
^,5 *
Centrifugal stress
I2WV*
Effective tension
(Tn-/n)
H.P. transmitted.
Centres pulley grooves.
Dia. of smallest pulley.
ins.
sq. ins. •1963
Ibs. -08 1
Ibs. 47
Ibs. 16
Ibs. 31
4'43
ins.
I-
ins.
T5
I
•3067
-125
72
24
48
6-84
I
18
i
•4417
-184
106
35
7*
10*07
l£
22
i
*6ol3
*25
144
48
96
13-67
TI15-
26
* -7854
'33
190
63
127
18-05
4
3°
1 | i I ' 2 2 7 2
•51
294
98
196
27-9
!TT
37
i£ ! 1-7671
"74
426
142
284
-10-48
4
45
if 2-4053
1 'OO
576
192
384
54'7
4
52
2 i 3*1416
i'3°
75°
250
500
7 no
2i
60
The centrifugal stress is weight per foot x z/2 -r £-, and the
fourth and sixth columns assume that /n = '2 Tn which gives Tn :
Vn : : 5 : i. From the tension formula,
Log. 5 or 69897 - '4343 x (/* x 2*613) x JSJ112L£?
27-463
--18
i|7/ is the usual diameter for main rope.
Fig. 545 shews a spinning-mill driven by cotton ropes, the
power being-given to five floors by separate sets of ropes, a good
arrangement in case of breakdown. The slack side being upper-
most gives a large arc of contact. Fig. 546 shews a travelling
crane. The rope is endless, passing round the pullies D, H, A, G,
F, and E in succession, and kept taut by the weight at H. Worm
gear is used in taking off the power, at E for travelling, at B for
lifting and lowering, and at c for cross-traversing; and either rope
is put in gear by the press pullies a, fr, actuated by hand levers P, Q
E is reversed by friction gear worked from handle L.